ASTR BLACK HOLES

Transcription

1 Overview/Preview [Image by A. Hamilton] ASTR BLACK HOLES Rosalba Perna - Fall 2012

2 WHAT IS A BLACK HOLE? A few definitions from the dictionary: Region of space resulting from the collapse of a star Region of space with strong gravitational field Dungeon or dark cell in a prison Project that requires large effort with no return Concentration of mass with a gravitational field so strong that not even light can escape its grip (closer to what this course will be about )

3 Starting point: our familiar world of slow human beings Slow compared to what???. the velocity of light, c

4 In our everyday, slow world, everybody agrees on measurements of time and space independently of the motion This constitutes our common sense

5 What happens when V c? Special Relativity - Einstein 1905

6 Relativity of.. Space Time and

7 Then GRAVITY comes into play.. + relativity of space and time General Relativity Einstein 1915

8 BLACK HOLES are predicted. Schwarzschild discovers that General Relativity predicts the presence of singularities, regions where gravity is so strong that not even light can escape Einstein refutes too bizarre to be true. but research continues.

9 Properties of Black Holes e.g. From inside this region no information can escape red-shifted red-shifted into oblivion Time dilation, gravitational redshift, spaghettification No hair theorem. Hawking radiation. Kerr black Holes.

10 Exotic phenomena connected to Black Holes. Wormholes Time machines

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12 Theoretically: Black holes believed to be associated with the death of massive stars

13 Observationally: several pieces of evidence (astrophysicists like to classify by the mass of the Sun) ) Small-mass BHs in X-ray binaries a few Supermassive BHs in galaxy centers and Quasars

14 X-RAY BINARIES Star feeding Black Hole QUASARS L~10 46 erg/s ~ L sun!!

15 Do we ever witness the birth of a NEW Black Hole? We probably do when we see a. GAMMA-RAY BURST

16 We will also discuss The BIG BANG theory.. and The theory of INFLATION

17 A class will also be on Black Holes and Popular Culture Excerpts from popular movies will be watched and discussed.

18 Focus of course: CONCEPTS, IDEAS Required math background: high school-level algebra But if you see something you don t like DO LET ME KNOW!

19 If you find some of these concepts and ideas mind bogglers.

20 DO NOT DESPAIR!!! YOU ARE NOT ALONE! Some concepts defy our everyday intuition

21 GOALS of the course: Understand where concept of Black Hole comes from within context of General Relativity Become familiar with physical properties of Black Holes Gain a knowledge of the current status of the astrophysical evidence for the presence of black holes in the Universe

22 Hopefully by the end of the course YOU WILL: Be able to evaluate critically the things you read in the popular press and science fiction literature Have a glimpse of the process by which scientific theories are conceived, advanced and tested Understand enough to be able to offer correct explanations of black holes and related phenomena to friends and family and have an idea of how science works.and all this while

23 .having FUN!

24 However, BE AWARE that: FUN EASY!!! You will need to have a good understanding of the material discussed in class in order to get the grade you aim at.

25 CLASS ATTENDANCE IS VERY IM PORTANT!! Questions on tests that count towards grade will always be on topics discussed in class. Clicker questions will yield minimum gain for no answer (more on this later). 90% of success is showing up. Woody Allen

26 Practicalities. This is a multi-media class. Lectures will be a mixture of: Demonstrations/explanations on the blackboard; Powerpoint presentations (images/clips) Videos and movies with discussions Practice problems Clicker questions followed by discussion

27 Field Trips to the Fiske Planetarium Prof. Dick McCray will host a show on Supernovae Prof. Andrew Hamilton will host a show on Black Holes

28 The Fiske planetarium team will host a show on The Milky Way, a City of Stars Guest Lecture: Prof. Webster Cash on MAXIM on Galaxies

29 Textbooks: Begelman & Rees Gravity final attraction Thorne: Black Holes and Time Warps NOTES from class If you do happen to miss a class, make sure to get a copy of the class lecture notes.

30 What YOU will need to do and GRADING policy 40% : 4 in class projects (3 people) - the best 3 count counts for 13.33% each. The worst will be neglected. 20%: paper (on a topic of your choice related to class) 30%: final (December 15) 10% clicker questions (on most days)

31 More on Clicker Questions: 3 Types of questions: On the material from the previous or recent classes (graded); On issues that arise in class and that are related to the material being discussed (graded); On background material not previously discussed- for me to know whether to make a digression (not graded) Assessment: Right answer: 2 points Wrong answer: 1 point No answer: 0 points 4 days bonus (i.e. 4 days of absence will discounted)

32 PROF: Office hours and contact info: Tue: 3:30pm-5:00pm Thu: 12:30pm-2:00pm 903 in JILA tower Tel: TA: Mon: 11:00am-12:30pm Wed: 11:00-12:30pm Duane 152 Tel: Course web site: